Housingless plate heat exchangers are known in the art having plates secured in a plate stack with a collecting tank or header on one or more ends. In some heat exchangers of this type, a valve is used to allow regulation of the fluid flow(e.g., an exhaust stream) through the collecting tank. Unfortunately, heretofore manufacturing costs for heat exchangers have been relatively high, especially because of the not insignificant assembly costs for the valve.
This is the case with, as an example, the exhaust heat exchanger known from DE 101 42 539 A1 (which, however, is not a housingless plate heat exchanger). De 101 42 539 A1 teaches manufacturing the exhaust heat exchanger by welding connections, which is fairly costly. Welding methods also appear to be the preferred connection technique in the exhaust heat exchanger taught in DE 199 62 863 A1 (also not a housingless plate heat exchanger). In EP 916 837 A2, a valve is screwed onto the end of the heat exchanger in a housing, which will also cause significant manufacturing costs. The exhaust line is detachably fastened to the housing.
Valve components that are guided with their stem through two openings of a jacket tube, through which an exhaust stream can be guided, which is controllable by means of a flap fastened to the stem, are known from German applications DE 101 42 411 A1 and DE 101 44 293 A1. However, such arrangements also appear to cause enormous manufacturing expense, since numerous assembly operations must be conducted to manufacture the entire heat exchanger.
The present invention is directed toward overcoming one or more of the problems set forth above.